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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.applet;

import java.awt.Image;
import java.awt.Graphics;
import java.awt.image.ColorModel;
import java.net.URL;
import java.util.Enumeration;
import java.io.InputStream;
import java.io.IOException;
import java.util.Iterator;

/**
 * This interface corresponds to an applet's environment: the
 * document containing the applet and the other applets in the same
 * document.
 * <p>
 * The methods in this interface can be used by an applet to obtain
 * information about its environment.
 *
 * @author Arthur van Hoff
 * @since JDK1.0
 */
public interface AppletContext {

  /**
   * Creates an audio clip.
   *
   * @param url an absolute URL giving the location of the audio clip.
   * @return the audio clip at the specified URL.
   */
  AudioClip getAudioClip(URL url);

  /**
   * Returns an <code>Image</code> object that can then be painted on
   * the screen. The <code>url</code> argument that is
   * passed as an argument must specify an absolute URL.
   * <p>
   * This method always returns immediately, whether or not the image
   * exists. When the applet attempts to draw the image on the screen,
   * the data will be loaded. The graphics primitives that draw the
   * image will incrementally paint on the screen.
   *
   * @param url an absolute URL giving the location of the image.
   * @return the image at the specified URL.
   * @see java.awt.Image
   */
  Image getImage(URL url);

  /**
   * Finds and returns the applet in the document represented by this
   * applet context with the given name. The name can be set in the
   * HTML tag by setting the <code>name</code> attribute.
   *
   * @param name an applet name.
   * @return the applet with the given name, or <code>null</code> if not found.
   */
  Applet getApplet(String name);

  /**
   * Finds all the applets in the document represented by this applet
   * context.
   *
   * @return an enumeration of all applets in the document represented by this applet context.
   */
  Enumeration<Applet> getApplets();

  /**
   * Requests that the browser or applet viewer show the Web page
   * indicated by the <code>url</code> argument. The browser or
   * applet viewer determines which window or frame to display the
   * Web page. This method may be ignored by applet contexts that
   * are not browsers.
   *
   * @param url an absolute URL giving the location of the document.
   */
  void showDocument(URL url);

  /**
   * Requests that the browser or applet viewer show the Web page
   * indicated by the <code>url</code> argument. The
   * <code>target</code> argument indicates in which HTML frame the
   * document is to be displayed.
   * The target argument is interpreted as follows:
   *
   * <center><table border="3" summary="Target arguments and their descriptions">
   * <tr><th>Target Argument</th><th>Description</th></tr>
   * <tr><td><code>"_self"</code>  <td>Show in the window and frame that
   * contain the applet.</tr>
   * <tr><td><code>"_parent"</code><td>Show in the applet's parent frame. If
   * the applet's frame has no parent frame,
   * acts the same as "_self".</tr>
   * <tr><td><code>"_top"</code>   <td>Show in the top-level frame of the applet's
   * window. If the applet's frame is the
   * top-level frame, acts the same as "_self".</tr>
   * <tr><td><code>"_blank"</code> <td>Show in a new, unnamed
   * top-level window.</tr>
   * <tr><td><i>name</i><td>Show in the frame or window named <i>name</i>. If
   * a target named <i>name</i> does not already exist, a
   * new top-level window with the specified name is created,
   * and the document is shown there.</tr>
   * </table> </center>
   * <p>
   * An applet viewer or browser is free to ignore <code>showDocument</code>.
   *
   * @param url an absolute URL giving the location of the document.
   * @param target a <code>String</code> indicating where to display the page.
   */
  public void showDocument(URL url, String target);

  /**
   * Requests that the argument string be displayed in the
   * "status window". Many browsers and applet viewers
   * provide such a window, where the application can inform users of
   * its current state.
   *
   * @param status a string to display in the status window.
   */
  void showStatus(String status);

  /**
   * Associates the specified stream with the specified key in this
   * applet context. If the applet context previously contained a mapping
   * for this key, the old value is replaced.
   * <p>
   * For security reasons, mapping of streams and keys exists for each
   * codebase. In other words, applet from one codebase cannot access
   * the streams created by an applet from a different codebase
   * <p>
   *
   * @param key key with which the specified value is to be associated.
   * @param stream stream to be associated with the specified key. If this parameter is
   * <code>null</code>, the specified key is removed in this applet context.
   * @throws IOException if the stream size exceeds a certain size limit. Size limit is decided by
   * the implementor of this interface.
   * @since 1.4
   */
  public void setStream(String key, InputStream stream) throws IOException;

  /**
   * Returns the stream to which specified key is associated within this
   * applet context. Returns <tt>null</tt> if the applet context contains
   * no stream for this key.
   * <p>
   * For security reasons, mapping of streams and keys exists for each
   * codebase. In other words, applet from one codebase cannot access
   * the streams created by an applet from a different codebase
   * <p>
   *
   * @param key key whose associated stream is to be returned.
   * @return the stream to which this applet context maps the key
   * @since 1.4
   */
  public InputStream getStream(String key);

  /**
   * Finds all the keys of the streams in this applet context.
   * <p>
   * For security reasons, mapping of streams and keys exists for each
   * codebase. In other words, applet from one codebase cannot access
   * the streams created by an applet from a different codebase
   * <p>
   *
   * @return an Iterator of all the names of the streams in this applet context.
   * @since 1.4
   */
  public Iterator<String> getStreamKeys();
}
